Objective: To compare the effects of endothelial progenitor cells (EPCs) and endothelial outgrowth cells (EOCs) on the repair of injured vessels.
Methods: Mononuclear cells (MNCs) were isolated from rabbit peripheral blood by density-gradient centrifugation. EPCs and EOCs were obtained from the culture of MNCs and labeled with the cell dye CM-DiI for cells tracking. Eighteen rabbits were made into models of balloon-injured common carotid artery and then divided into 2 equal groups to undergo injection of the suspensions of EPCs or EOCs. Nine rabbits underwent injection of normal saline as control group. Four weeks after transplantation, the rabbits underwent venous injection of Evans blue, and then were killed with the injured vessels taken out. Fluorescence-labeled both types of cells, endothelial regeneration rate and IA/MA ratio were detected.
Results: Four weeks after transplantation, fluorescence-labeled EPCs and EOCs were detected within the tunica intima, mostly in the neointima and on the luminal surface of injured vessel. The endothelialization area of denuded vessel of the EPC and EOC groups were 91.6% +/- 3.6% and 89.1% +/- 6.3% respectively, both significantly larger than that of the control group (62.1% +/- 7.5%, both P < 0.01), however, without significant difference between the 2 former groups (P = 0.50). The intima area/media area ratio of the EPC and EOC groups were 0.48 +/- 0.11 and 0.44 +/- 0.06, both significantly lower than that of the control group (0.88 +/- 0.14, both P < 0.01), however, without significant difference between the 2 former groups (P = 0.59).
Conclusion: Transplantation of both EPCs and EPCs accelerate the reendothelialization and reduce the neointimal formation with similar effects.